Australian by Nature’s Calcium + Vitamin D provides above the daily dose amount of elemental calcium. During digestion, the elemental calcium is released from the compound (citrate) and becomes available for absorption. Vitamin D aids in the increased uptake and absorption of calcium. It also assists in maintaining muscle strength. Calcium is required for the development and maintenance of a healthy skeletal system. Requirements may increase dependent on age, gender, diet, pregnancy, lactation and post menopause. Australian by Nature is a consistent provider premium quality products. That is why we have formulated this product with Calcium Citrate over the most widely used Calcium Carbonate. Calcium Citrate is naturally derived from the calcium salt of citric acid and is well absorbed on an empty stomach. Unlike Calcium Carbonate which should be taken with meals as it requires extra stomach acid for digestion and absorption, and may cause constipation.